I'm a little north of 20 myself. Since my players are usually a notch below some of the elite teams I run into come playoff time, I feel the need for putting more than others into formations in order to make up for any talent differential come playoff time. Figure if my team isn't more talented, we'll at least be smarter (the team, not the coach, lol).
Overall, I do think my team plays better vs. when I set it at 20 or below. But, it could be just wishful thinking.